the god delusion [statistically speaking]

While in Bangalore, I spotted Richard Dawkins’ The God delusion in the [fantastic if chaotic] campus bookstore and bought the Indian edition for a nominal amount.  I read most of it during my week in Boston. And finished by the lake in Maine. While I agree with most of the points made in Dawkins’ book about the irrationality of religions, and of their overall negative impact on human societies, I found the first part rather boring in that I see little appeal in dissecting so minutely the [infinitely many] incoherences of religious myths and beliefs, as this will likely miss the intended target [i.e., literal believers]. Similarly, the chapter on evolution versus intelligent design made valuable points, albeit I had already seen them before. Nothing wrong with repeating those, in particular that evolution has little to do with chance, but again unlikely to convince the [fundamentalist] masses. Overall, the book mostly focus on the Judeo-Christian-Muslim branch of religions, which may reflect on the author’s own culture and upbringing but also misses the recent attempts of Buddhism to incorporate science into their picture.

“A universe in which we are alone except for other slowly evolved intelligences is a very different universe from one with an original guiding agent whose intelligent design is responsible for its very existence.” (p.85)

What is most interesting in the book (for me) is when Dawkins tries to set the God hypothesis as a scientific hypothesis and to apply scientific methods to validate or invalidate this hypothesis. Even though there is no p-value or quantitative answer at the end. Despite the highly frequent use of “statistical” and “statistically improbable” in the corresponding chapter. What’s even more fascinating is Dawkins’ take at Bayesian arguments! Either because it is associated with a reverent or because it relies on subjective prior assessments, Bayesian statistics does not fit as a proper approach. Funny enough, Dawkins himself relies on subjective prior probabilities when discussing the likelihood of find a planet such as Earth. Now, into the details [with the Devil1] in a rather haphazard order or lack thereof:

“A universe in which we are alone except for other slowly evolved intelligences is a very different universe from one with an original guiding agent whose intelligent design is responsible for its very existence.” (p.85)

I appreciated Dawkins’ debunking of the non-overlapping magisteria (NOMA) principle, namely that scientists should leave religion questions to philosophers and theologians. Restating that the “God Hypothesis” truly is a scientific question that must be addressed from a scientific perspective and hence by scientific means. Mentioning Francis Galton, “the first to analyse scientifically whether praying for the royal family is efficacious (…) [he] looked into it, and found no statistical difference.” (p.85)

“Arguments for God’s existence falls into two main categories, the a priori and the a posteriori.” (p.103)

Another interesting (if not particularly novel) remark is about the strong secularism of the “Founding Fathers” like Jefferson, Adams (John, not Douglas!) or Madison, who were most likely atheists. Which conflicts with the equally strong influence of religion in 21st-century America.

“Huxley, in his concentration upon the absolute impossibility of proving or disproving God, seems to have been ignoring the shading of probability.” (p.72)

While I do not feel the book is particularly strong from a philosophical viewpoint, I appreciated the section on agnosticism: the apparently reasonable sceptic attitude of refusing to commit for or against something that cannot be demonstrated does not stand once one starts piling creeds and beliefs like Russell’s teapot, against the absence of God. In Dawkins’ word, a 50 percent probability in favour of each hypothesis does not hold: “the odds in favour of the teapot are not equal to the odds against” (p.76). (Note that he does not fall into Templeton’s fallacy of reducing the probabilities of hypotheses by multiplying those hypotheses!) Connected funny remarks: as monotheism considers itself superior of polytheism (despite the myriads of characters in the Catholic pantheon), why not move one step further and subtract the remaining god? And the fact than an atheist is simply disbelieving in one god more (or less) than any monotheist.

“Bayes’ Theorem (…) is a mathematical engine for combining many estimated likelihoods and coming up with a final verdict, which bears its own quantitative estimate of likelihood. But of course that final estimate can only be as goof as the original numbers fed in. These are usually subjectively judged, with all the doubts that inevitably flow from that.” (p.133)

Dawkins thus spends five pages on some Bayesian arguments for God’s existence.  Surprisingly, he is missing the historical facts that Bayes and Pierce set the theorem into motion to answer Hume’s probabilistic arguments against the existence of miracles. And that one of Bayes’ few existing papers is about the existence of God. Dawkins does not aim at the whole Bayesian perspective when he starts from Stephen Uwin’s Probability of God. However, his [Dawkins’] criticism would equally apply to any Bayesian argument. He seems to see any subjective input or personal probability as a-scientific and akin to faith: “who cares about subjective judgements anyway?” (p.135) A pedantic remark is about Dawkins’ unusual meaning of likelihood, which he seems to understand as probability (of an hypothesis?) and even as posterior probability if I get the “estimated” right.

“The book is better seen as a `How To’ manual, a sort of Bayes’ Theorem for Dummies, using the existence of God as a semi-facetious case study (…) Uwin’s quixotic attempt to put a number on the probability is quite agreeably funny.” (p.132)

The above quote and the one introducing Bayes’ Theorem are surprising in that they reveal Dawkins’ perception of probability as a-numeric (and hence a-Bayesian). However, in a later chapter, he does not mind putting a (prior?) probability on “the odds of life originating spontaneously on a planet [as] a billion to one against” (p.165). And to argue that “any probability statement is made in the context of a certain level of ignorance” (p.166), a point followed by a description of what ends up being Bayesian updating!

“The trouble is that (to repeat) the six weightings are not measured quantities but simply Stephen Unwin’s own personal judgements, turned into numbers for the exercise.” (p.133)

Obviously, I cannot say much about Uwin’s arguments to reach 0.67 as the posterior probability of existence of God for a prior (agnostic) probability of 0.5 and six contributing facts. It seems rather weird to mix facts (e.g., Hitler existed) and beliefs (there might be miracles) selected out of the myriad possible statements about God’s existence, and use them naïvely into Bayes’ Theorem. I thus share Dawkins’ scepticism at this level. If not at the overall issue of putting personal and subjective assessments on non-reproducible events.

“When challenged by a zealous Popperian to say how evolution could ever be falsified, J.B.S. Haldane famously growled: `Fossil rabbits in the Precambrian’.” (p.154)

I found the part about cosmology and the anthropic principle less convincing than the seamless analysis of Darwin and the principle of biological evolution. While the very existence of our Universe is stupendous, the fact that it does exist does not imply in any way the deed of an higher being or the simultaneous existence of parallel universes. Or, even less so, a Darwinian sort of natural selection among multiverses (p.175). These are interesting intellectual constructs, but there is no evidence about them. At least within the book. To argue that “people who think [there is no difference with the God hypothesis] have not had their conscience raised by natural selection” (p.175) is not a scientific argument. Nor is the following line that the relative simplicity of the multiverse implies a higher “statistical improbability”. I also remain quite sceptical about the lyrical passages on the meme pool, as I am not convinced there is anything provable [or falsifiable!] in the concept. (Meme is a “unit of cultural inheritance”, p.222.)

Overall, this is a clearly needed book, which sweeps away common arguments about the societal benefits of religion(s). As written above, I concur with most of Dawkins’ points and while I think his arguments cannot reach fundamentalists who in the first place would not approach the book with anything but a flame-thrower, it may enlighten agnostics and doubters who hover at the fringe of [a] religion and who need a gentle push to jump to the other side of the border.